Make sure that you a following through on your shots and that your split stepping.
Give yourself more time than usual to get into the match. Play at 70 or even 50 percent of your normal power early in the match to get your rhythm established.
And, for this situation in particular, you win either way. If you lose the match and play on JV, you'll be getting match experience in a lower pressure situation. If you lost the match due to choking, then it's the best thing that can happen to you.